Electroluminescent-photoconductive triggering device



July 5, 1966 M. KRAWlTZ 3,259,794

ELECTROLUMINESCENT-PHOTOCONDUC'I'IVE TRIGGERING DEVICE Filed July 15,1963 3 Sheets-Sheet l Prior" Art INVENTOR Max K/awitz LZWZ/M ATTORN EYJuly 5, 1966 wrrz 3,259,794

ELECTROLUMINESCENT-PHOTOCONDUCTIVE TRIGGERING DEVICE Filed July 15, 19633 Sheets-Sheet 2 INVENTOR Max Kraw/tz Z MW ATTORNEY July 5, 1966 M.KRAWlTZ 3,259,794

ELECTROLUMINESCENT-PHOTOCQNDUCTIVE TRIGGERING DEVICE Filed July 15, 1963'5 Sheets-Sheet 5 INVENTOR Max Kraw/tz Z /MW ATTORN EY United StatesPatent 3,259,794 ELECTROLUMINESCENT-PHOTOCONDUCTIVE TRIGGERHNG DEVICEMax Krawitz, Seneca Falls, N.Y., assignor to Sylvania Electric ProductsInc., a corporation of Delaware Filed July 15, 1963, Ser. No. 295,127 3Claims. (Cl. 315-451) This invention relates to the sequentialtriggering of lamps. In particular it relates to the triggering ofelectroluminescent lamps utilizing a chain reaction to illuminate anydesired number of these lamps.

In some forms of signal devices or display devices it is necessary toprovide a bank of lamps, each individually controlled by its own switch,with the lamps arranged in such a circuit that when a particular lamp isilluminated a number of others will sequentially be illuminated. Where alarge number of lamps are involved, the time period required toilluminate the desired number of lamps may be too long. Thus the timerequired for illuminating an electroluminescent lamp is aboutmilliseconds. If 50 lamps were employed, then the time required toilluminate all these lamps, were they lit in a chain reaction, would be500 milliseconds. This time period, for some purposes, may cause toomuch of a delay in the operation of the lamps.

It is an object of this invention to provide a circuit which shallshorten the time required to illuminate a desired number of lamps andyet provide for selective operation of any number of lamps in a bank.

For a better understanding of the present invention, together with otherand further objects, advantages, and capabilities thereof, reference ismade to the following disclosure and appended claims in connection withthe accompanying drawings in which:

FIG. 1 is a circuit diagram of a known form of display device utilizingelectroluminescent lamps;

FIG. 2 is a circuit diagram, in accordance with the invention, utilizinga means for illuminating a desired number of lamps in a short period oftime; and

FIG. 3 is a similar diagram showing a modification of the invention.

Referring more in detail to the prior art of FIG. 1, it will be notedthat the same discloses a pair of mains 10 and 12 coupling with an A.C.generator 14. Bridging the mains are electroluminescent lamps, each inseries with a switch. Thus as illustrated in FIG. 1, there is disclosedfive combinations of electroluminescent lamps and switches, 20, 21; 22,23; 24, 25; 26, 27; and 28, 29. Associated with each of theelectroluminescent lamps and in a position to be irradiated by theselamps are photoconductive cells. The photoconductive cell 31, inposition to be irradiated by the electroluminescent lamp 2%, is in shuntrelation to the switch 23. Similarly, the photoconductive cell 32associated with the lamp 22 shunts the switch 25; photoconductive cell33 shunts switch 27; photoconductive cell 34 shunts switch 29;photoconductive cell 35 shun-ts the next switch 30; and so on down theentire number of electroluminescent lamps and associated photoconductivecells and switches.

When any switch, such as switch 23, is closed, the associated lamp 22will be caused to become luminescent thereby irradiating the associatedphotoconductive cell 32 and lowering its resistance so that the voltageimposed on the next electroluminescent lamp 24 in the chain of lampsbecomes sutficiently high to illuminate the lamp. This lamp 24 in turnwill lower the resistance of photoconductive cell 33 thereby causinglamp 26 to become luminescent, and so on down the chain of lamps. Itwill be noted by this prior art arrangement that the period of timerequired for illuminating all the lamps is in direct proportion to thenumber of lamps in the chain and the time required to illuminate one ofthem.

In accordance with the invention and disclosure in FIG. 2, the timerequired to illuminate a desired number of lamps is substantiallyhalved.

In FIG. 2 there is illustrated a pair of mains 10 and 12, as before, anda generator 14 connected to the mains via a switch 36. Shunting themains are series connected electroluminescent lamps and switches. In thedrawing six such lamps and series connected switches are illustrated,namely, 40, 41; 42, 43; 44, 45; 46, 47; 48, 49; and 50, 51. It isobvious that as many more such combinations of lamps and switches may beutilized as may be desired. Associated with the lamp 40 are twophotoconductive cells 53 and 54. Associated with the next lamp 42 isonly one photoconductive cell 55. Succeeding electroluminescent lampslikewise have associated with them, in alternation, two photoconductivecells and one photoconductive cell. Referring back to thephotoconductive cells 53 and 54, photoconductive cell 53 shunts switch43 which is associated with the next lamp 42 in the bank of lamps.Photoconductive cell 54 shunts the switch 45 which is associated withthe second lamp 44 beyond the lamp 40. Thus with the main switch 36closed, closure of switch 41 effects illumination of lamp 40. As aresult, both photoconductive cells 53 and 54 would be irradiated toenergize not only the lamp 42 but also lamp 44. Lamp 44 in turn wouldirradiate the pair of photoconductive cells 56 and 57, and these in turnwould energize lamps 46 and 48 and so on down the chain of lamps. Thusthe time required to illuminate the lamps would be about one-half thatwhich is required to illuminate the same number of lamps in accordancewith circuitry of FIG. 1. Since it is desirable to use as fewphotoconductive cells as possible, alternate electroluminescent lampssuch as 42, 46, 50, and so on are associated with only a singlephotoconductive cell as 55, 58, and 61. However, an initial illuminationof a lamp associated with a single cell, as by closure of switch 43,would short the switch of the next lamp; Since the next lamp has twophotoconductive cells associated with it, the double chain reactionpreviously disclosed will take place. The time required for illuminationof these lamps in this circumstance would therefore be about one-halfthe time required to illumi nate a similar number of lamps in accordancewith the arrangement of FIG. 1 plus the time required to illuminate theone additional lamp 42. It is obvious that opening of switch 36 willextinguish all of the lamps in the bank which had been lit.

In accordance with the circuitry of FIG. 3, the time required toilluminate the lamps is substantially one-third that required toilluminate a similar number of lamps in FIG. 1. As in FIG. 2, mains 10and 12 are provided as well as the generator 14 and the main switch 36.As in the previous form of the invention, there will be provided anumber of lamps and associated series connected switches such as 62, 63;64, 65; 66, 67; 68, 69; 70, 71; 72, 73; 74, 75; and so on. Associatedwith the electroluminescent lamp 62 are three photoconductive cells 76,77, and 78. Photoconductive cell 76 shorts switch 65 of the next lamp 64in the chain; photoconductive cell 77 shorts switch 67 of the lamp 66twice removed from the lamp 62; and photoconductive cell 78 shortsswitch 69 thrice removed from the lamp 62.

Upon closure of main switch 36 and the selected one of the seriesconnected switches, for example switch 63, the three photoconductivecells will be irradiated thereby causing illumination of the next threelamps 64, 66, and 68. Illumination of lamp 68 will irradiate a likenumber of three cells 79, 80, and 81 and these simultaneously will shortthe switches 71, 73, and 75 thereby causing illumination of the nextthree lamps 70, 72, and 74. In a like manner, the illumination of lamp74 will irradiate three other photoconductive cells thus continuing thechain reaction down the bank of lamps. Associated with a second one of atriad of lamps, as lamps 64 and 70, are two photoconductive cells 82 and83, the cell 82 shunting the switch 67 and the cell 83 shunting theswitch 69. Should the series switch 65 be closed, instead of switch 63,to illuminate lamp 64 and the lamps further down in the bank of lamps,the lamps controlled by switches above switch 65 will not beilluminated. Note that the two lamps 66 and 68 below lamp 64 will beilluminated simultaneously. Since lamp 68 is illuminated, the, triplechain reaction previously described will again take place. Associatedwith the third of the triad of lamps is a single photoconductive cell84, this cell shorting switch 69. When this cell is irradiated, as forexample by closure of switch 67, the lamp 68 will become illuminated,irradiating the three photoconductive cells associated therewith againcausing the triple chain reaction of the illumination of the differentlamps as heretofore described. Thus the time required for illuminatingthe lamps of a bank in accordance with the circuitry of FIG. 3 issubstantially onethird that required with the circuitry of FIG. 1. It isto be noted that there is a saving in the use of photoconductive cells,each triad of lamps such as 62, 64, and 66 having associated therewithphotoconductive cells in descending numbers, as three cells for lamp 62,two cells for lamp 64, and one cell for lamp 66. It is obvious from theabove that groups of four or more lamps and associated descending orderof photoconductive cells may be utilized to save still more time in thelighting of a selected number of lamps.

Thus the applicant has provided means whereby time may be gained in theillumination of a desired number of lamps in a bank of lamps coupledwith a saving in the number of photoconductive cells required to beassociated with the lamps. While the switches in series with the lampsand the generator are illustrated as knife switches, it is obvious thatthey may be of any character desired so long as they perform a switchingfunction.

While there have been shown and described what are at present consideredthe preferred embodiments of the invention, it will be obvious to thoseskilled in the art that various changes and modifications may be madetherein without departing from the invention as defined by the appendedclaims.

Having thus described my invention, what is claimed is:

1. Means for triggering lamps to become lit comprising an energizingsource, a lamp, and a switch in series therewith connected to theenergizing source, a number of photoconductive cells adapted to beirradiated by the lamp, a second lamp and series connected switchconnected to the energizing source, a number of photoconductive cellsadapted to be irradiated by the second lamp, there being one lessphotoconductive cell irradiated by the second lamp than by the firstlamp, a third series connected lamp and switch across the energizingsource, and at least one photoconductive cell irradiated by said thirdlamp, one of the photoconductive cells of the first lamp bridging theswitch of the second lamp, a second photoconductive cell of the firstlamp bridging the switch of the third lamp, the photoconductive cellassociated with the second lamp bridging the switch of the third lampand the photoconductive cell adapted to be irradiated by the third lampadapted to bridge yet another switch.

2. Means for triggering a desired number of lamps to be lit comprisingan energizing circuit, groups of lamps across said energizing circuit,each lamp of the group having a switch in series with the lamp andphotoconductive cells associated with the lamps in position to beirradiated by the lamps, the first lamp being adapted to irradiate anumber of such cells, the second lamp of the group being adapted toirradiate one less member of photoconductive cells and succeeding lampsof the group adapted to irradiate successively one less photoconductivecell, each photoconductive cell being in shunting relation to a switchof another lamp.

3. Means for triggering lamps arranged in groups to be lit comprising anenergizing circuit, each lamp of a group having a switch in seriestherewith in the energizing circuit and each lamp having photoconductivecells individual thereto in position to be irradiated by the lamp, afirst lamp of the group irradiating a multiplicity of said cellsindividual thereto and each succeeding lamp of the group irradiating oneless cell individual to it, said cells each bridging a switch of a lampnot irradiating said cell.

No references cited.

DAVID J. GALVIN, Primary Examiner.

R, JUDD, Assistant Examiner.

1. MEANS FOR TRIGGERING LAMPS TO BECOME LIT COMPRISING AN ENERGIZINGSOURCE, A LAMP, AND A SWITCH IN SERIES THEREWITH CONNECTED TO THEENERGIZING SOURCE, A NUMBER OF PHOTOCONDUCTIVE CELLS ADAPTED TO BEIRRADIATED BY THE LAMP, A SECOND LAMP AND SERIES CONNECTED SWITCHCONNECTED TO THE ENERGIZING SOURCE, A NUMBER OF PHOTOCONDUCTIVE CELLSADAPTED TO BE IRRADIATED BY THE SECOND LAMP, THERE BEING ONE LESSPHOTOCONDUCTIVE CELL IRRADIATED BY THE SECOND LAMP THAN BY THE FIRSTLAMP, A THIRD SERIES CONNECTED LAMP AND SWITCH ACROSS THE ENERGIZINGSOURCE, AND AT LEAST ONE PHOTOCONDUCTIVE CELL IRRADIATED BY SAID THIRDLAMP, ONE OF THE PHOTOCONDUCTIVE CELLS OF THE FIRST LAMP BRIDGING THESWITCH OF THE SECOND LAMP, A SECOND PHOTOCONDUCTIVE CELL OF THE FIRSTLAMP BRIDGING THE SWITCH OF THE THIRD LAMP, THE PHOTOCONDUCTIVE CELLASSOCIATED WITH THE SECOND LAMP BRIDGING THE SWITCH OF THE THIRD